fix issue 25: change file extension on format select

[leanne63]

Added IBAction for the mAExportAs.xib buttons. When clicked, the extension on the savePanel filename is changed as follows:

• No format selections: .<error>
• More than one format selection: .*
• One format selection: the appropriate extension for the selection (.wav, .ogg, .m4a, .mp3)

mADocumentExporter is using the exportAs... values, rather than the actual filename extension, to determine the export file extension. Therefore, upon saving, the filename extension is changed back to .wav (as expected by mADocumentExporter).

Also upon saving, if no other formats have been selected, exportAsWAV is set to YES. If other formats have been selected, this is left as is. Again, this is because mADocumentExporter is using the exportAs... values, rather than the actual filename extension, to determine the export file extension.

Added property for mAExportAsViewController connection to miniAudicleDocument savePanel so can retrieve the save panel's setAllowedFileTypes method.

[spencersalazar]

Thanks a ton Leanne! This is great. A couple of comments-

• if you export once, select something besides or in addition to WAV, and then export a second time, the file path shows ".wav" again instead of .*

• . is a little confusing to me, I think its better to just display nothing (no extension, just the basename) and maybe disable the export button if possible

[leanne63]

I'll make those changes and post an update, Spencer.

[leanne63]

• if you export once, select something besides or in addition to WAV, and then export a second time, the file path shows ".wav" again instead of .*

The filename now displays the correct extension upon first export and all successive exports.

• .<error> is a little confusing to me, I think its better to just display nothing (no extension, just the basename) and maybe disable the export button if possible

If no selections exist, the filename (or the default "untitled") is present without any extension. The panel also displays a message noting that format(s) must be selected. The Export button is disabled until at least one selection is made.

Note: An attributed string can't be used for the message text, so the text color and appearance is just plain black. However, the way the message pops up makes it apparent to the user that something must be done, with the text explaining what that is (select formats).

Ah, also note: I noticed the previous code was using spaces, while my code had tabs. To make everything consistent, I switched the tabs to spaces in Xcode for those files I edited.

[spencersalazar]

Awesome thanks again! This is great. I fixed a couple of things before merging-

• added NSPanel+ButtonTag.m to the makefile.osx (makefile-based build is technically the "official" build)
• set the allowedFileTypes property to nil if none of file types are selected. This causes the panel to show the last extension used instead of no extension, but avoids a seeming bug in AppKit where the Panel adds extra periods after the first one(?) At least thats what Im seeing on Mac OS X 10.11.5- if theres a better solution happy to use that instead, but this seems better for the time being.